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Google open sources Apache server speed mod

Googlenet mystery server bits?

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Google has open sourced an Apache server module designed to speed website performance. Presumably, the module is based on the mystery Google Web Server the company uses to serve its own pages.

Known as "mod_pagespeed," the Apache module speeds performance "on the fly" in 15 separate ways, which include optimizing page caching, minimizing client-server round trips, and reducing payload size. "mod_pagespeed is an open-source Apache module that automatically optimizes web pages and resources on them," Google says. "It does this by rewriting the resources using filters that implement web performance best practices. Webmasters and web developers can use mod_pagespeed to improve the performance of their web pages when serving content with the Apache HTTP Server."

The module can change pages built by your content management system (CMS) without requiring changes to the CMS itself, and when an image's HTML context changes, it can re-compress the image so that only the required bytes are served. It includes several filters for optimizing JavaScript, HTML, and CSS stylesheets, and additional filters for JPEG and PNG images.

Google says it has seen the module reduce page load times by up to 50 per cent on a random sample of sites. "In other words, [it's] essentially speeding up websites by about 2x, and sometimes even faster," the company said in a blog post.

Google shows off a sample test here:

Google says it's already working with GoDaddy to run the Apache module with "many" of the hosting outfit's 8.5 million customers, and it's partnering with Contendo to integrate the module with that company's content delivery network.

You can download the module here. Google offers 32-bit and 64-bit binaries, and it has been tested on CenOS and Ubuntu, but it may also run on other Debian-based and RPM-based Linux distros. It requires Apache 2.2.

According to the latest study from UK research outfit Netcraft, the Google Web Server — a custom-built server originally based on Apache — now runs nearly 13 per cent of all active web sites. This includes not only Google's own sites, but also the sites it runs on behalf of third parties via services like Blogger, Google App Engine, and Google Sites.

Apache is the most prevalent server on the web, running 53,651,190 active sites, compared with 16,118,218 run by Microsoft servers and 11,978,680 run by Google Web Server (aka GWS, pronounced "gwiss"). But GWS is only run within the Googlenet.

Asked if its mod_pagespeed Apache module is based on GWS, Google did not respond. But it's typically tight-lipped about its internal technology. A former Google employee has told The Reg that GWS was originally built from open source Apache code. But, according this ex-employee, the server has been so heavily modified over the years that it now bears little resemblance to Apache. It's packed with custom I/O handles, he says, that interface with Google-specific remote procedure calls.

But Google is presumably using the speed optimizations it's now offering to world+dog through the mod_pagespeed module. The module's open source project is here. ®